MicroScream: Under Voltage Alarm for LiPo/Li-Ion Batteries

"Alarm will sound at 6.0V for 2 cells and 9.0V for the 3 cell configuration.

Current draw: 5.5mA @ 7.4V (alarm off) : 29mA at 6.0V (alarm on).

Simple ‘dead bug’ construction weight was 2.9 grams.

Construction and use of this device (circuit) is at your own risk and liability."

* Note from RDL site Admin = I have used this circuit many times for triggering a FET at a specific voltages, in different circuits, as well as it's intended use in RC devices that lack a built-in alert for low LiPo voltage. Scale and adjust to your own peril/benefit.